The Internet infrastructure has grown continually and significantly over the recent years. In conjunction with this growth, traditional telephony services continue to migrate to new platforms and protocols that operate via the Internet. The increasing use of Internet telephony has spurred development and introduction of numerous telephony services. The widespread use of standardized Internet telephony protocols as an interface help assure that a user and a server can rely on a commonly used method for exchanging information.
Internet telephony involves the transport of real-time media, such as voice and video, over the Internet to provide interactive communication among Internet users. Unlike a circuit-based system (e.g., existing telephone system such as a Public Switched Telephone System (PSTN)), Internet Protocol (IP) telephony is a packet-based communication system. In a packet-based system, packets of data are routed over a network to reach a destination.
Currently, traditional PSTN telephony uses SS7 (Signaling System 7) as the signaling protocol which establishes, controls, and tears down circuit connections. On the other hand, IP telephony uses Session Initiation Protocol (SIP) as the signaling protocol for telephony, videoconferencing, and multimedia sessions. SIP is a data-oriented protocol used by source and destination end devices for communicating data across a packet-based communication system.
A SIP system consists of a network server and an end device (also known as a client device). The end device is an end system that acts on behalf of someone who participates in calls. Further, there are two different types of network servers (i) a proxy server, which receives requests, determines which server to send it to, and then forwards the request, and (ii) a redirect server, which receives requests, but instead of forwarding them to the next proxy server, tells the client to contact the next proxy server directly. The SIP system may include multiple network servers or end devices.
In traditional telephone systems, a Private Branch Exchange (PBX) is a private network used for business voice communication. The PBX is a subscriber-owned telecommunications exchange that usually includes access to a public switched telephone network (PSTN). The functions of the PBX include connecting end devices such as telephones, and maintaining such connections. The PBX offers various feature-based services such as voicemail, music on hold, call forwarding, and conferencing, to name a few. The feature-based services may be activated through service-specific buttons on end devices.
Traditional PBXs manage and control feature-based services through a PBX server. As an example, a user provides an input to activate a feature through service-specific buttons on a conventional telephone. The input is then transmitted to the PBX server that activates the feature.
Increasingly, traditional PBXs are being phased out. On the other hand, PBXs used in conjunction with an Internet Protocol, hereby known as an Internet Protocol Automatic Branch Exchanges (IPABX), are becoming common. The replacement of traditional PBXs with IPABXs will require that users have the same services from their IP-enabled desktop telephone that they previously had from their traditional PBX telephone.
Typical communication mechanisms used to convey so-called feature data from an end device to a PBX or IPABX are custom-designed messaging systems. That is, an end device (hereby referred to as a client device), such as a Voice over Internet Protocol (VOIP) enabled telephone or a telephone configured with SIP, provides data to the IPABX using a proprietary message format and signaling scheme that is unique to the particular IPABX system. The inventors have discovered that a generic and standardized mechanism to invoke feature-based services through the client device is desirable. The present invention proposes a mechanism to achieve the activation of feature-based services in an IPABX system.